Chalk streams are rivers that rise from springs in landscapes with chalk bedrock. Since chalk is permeable, water percolates easily through the ground to the water table and chalk streams therefore receive little surface runoff. As a result, the water in the streams contains little organic matter and sediment and is generally very clear. [c]
The beds of the rivers are generally composed of clean, compacted gravel and flints, which are good spawning areas for Salmonidae fish species.[3] Since they are fed primarily by aquifers, the flow rate, mineral content and temperature range of chalk streams exhibit less seasonal variation than other rivers.[3][4] They are mildly alkaline[5] and contain high levels of nitrate, phosphate, potassium and silicate.[3] In addition to algae and diatoms, the streams provide a suitable habitat for macrophytes (including water crowfoot)[6] and oxygen levels are generally supportive of coarse fish populations.[3]
Of the 210 rivers classified as chalk streams globally, 160 are in England.[5]
A list of chalk streams in England gives a total of 224.[g]
Chalk is a highly porous and permeable rock, and rain falling onto chalk topography percolates directly into the ground, where the chalk layer acts as an aquifer. The groundwater flows through the chalk bedrock, re-emerging lower down the slope in springs. The chalk acts as a temporary reservoir by regulating the amount of water supplied to the springs. This is why many chalk streams in the UK have stable flow regimes that vary only slightly over time. The temperature of the emerging surface water is fairly stable and rarely deviates from 10 °C (50 °F). On cold winter mornings, water vapour from the relatively warm stream condenses in the cold air above to form fog.
Chalk is slightly soluble in rainwater because rain is naturally slightly acidic.[7] The products of chalk weathering are dissolved in rainwater and are transported in stream flow. Chalk streams transport little suspended material (unlike most rivers), but are considered "mineral-rich" due to the dissolved calcium and carbonate ions. The surface water of chalk streams is commonly described as "gin clear". The channel bed consists of angular flint gravel derived from the natural flint deposits found embedded within the chalk geology that contains relatively low amounts of clay and silt deposits.
The unique characteristics of chalk stream ecology are due to stable temperature and flow regimes combined with highly transparent water and lack of sand grade sediment particles.
The chalk streams have been intensively managed for many generations. In the 20th and 21st centuries, much of that management has been aimed at producing the best conditions for fly fishing, and most specifically, dry fly fishing. The chalk streams hold a good number of wild salmonid fish species such as the brown trout (Salmo trutta), and grayling (Thymallus thymallus). In addition to these there are also considerable numbers of stocked brown trout and stocked rainbow trout (Oncorhynchus mykiss). The rich invertebrate life and characteristic transparent shallow water make chalk rivers and streams particularly suited to fly fishing.
Many of the chalk stream springs are also used as sites for watercress production, due to the constant temperature and clean, alkaline, mineral-rich spring water.[h] The Mid Hants Watercress Railway in Hampshire is so named on account of its use for transporting watercress to London from local chalk streams. A number of the chalk aquifers and associated groundwater sources related to chalk streams and rivers are used for water abstraction by local and national water utility companies.
Although chalk streams are generally watercourses originating from chalk hills, including winterbournes, streams, and rivers, the term chalk stream is used even for larger rivers, which would normally be considered too large for the term stream. The Somme in northern France is a chalk stream on a larger scale.
Winterbournes[i] are known by different names depending on region:
Chalk streams of the Southern England Chalk Formation in Berkshire, Hampshire, Wiltshire, Dorset and the Isle of Wight:
Chalk streams of the Southern England Chalk Formation in the Chiltern Hills, Hertfordshire and Surrey (tributaries of the River Thames, River Lea and River Colne):
Chalk streams of the Yorkshire Wolds:
Chalk streams of Lincolnshire:[9] There are several chalk streams in the Lincolnshire Wolds including
Chalk streams of Kent:
Chalk streams of Norfolk:[10]
Chalk streams of Suffolk:
هذه المقالة يتيمة إذ تصل إليها مقالات أخرى قليلة جدًا. فضلًا، ساعد بإضافة وصلة إليها في مقالات متعلقة بها. (أغسطس 2019) اضغط هنا للاطلاع على كيفية قراءة التصنيف سحلب الرسن المرتبة التصنيفية جنس التصنيف العلمي فوق النطاق حيويات مملكة عليا حقيقيات النوى مملكة …
У этого термина существуют и другие значения, см. Бар. ГородБарукр. Бар Флаг Герб 49°04′41″ с. ш. 27°40′59″ в. д.HGЯO Страна Украина Область Винницкая Район Жмеринский Община Барская городская История и география Основан 1401 Первое упоминание 1425[1] Прежние назван
У этого топонима есть и другие значения, см. Арбор. СелоАрбортат. Арбор 56°32′53″ с. ш. 50°12′44″ в. д.HGЯO Страна Россия Субъект Федерации Татарстан Муниципальный район Балтасинский Сельское поселение Ципьинское История и география Основан XVI век Первое упоминани
Nanatsu no Taizai beralih ke halaman ini. Untuk waralaba media milik Hobby Japan dengan nama Jepang yang sama, lihat Seven Mortal Sins. Artikel ini bukan mengenai tujuh dosa pokok. Seven Deadly SinsGambar sampul manga volume pertama七つの大罪(Nanatsu no Taizai)GenrePetualangan, fantasi[1] MangaPengarangNakaba SuzukiPenerbitKodanshaPenerbit bahasa InggrisNA Kodansha USACrunchyroll (digital)Penerbit bahasa IndonesiaElex Media KomputindoMajalahWeekly Shōnen MagazineDemografiShōnenTer…
Favorite History NameFavorite Port of registryCoos Bay, Oregon, later Empire, Oregon BuilderEllingson, Coquille, Oregon In service1901 IdentificationU.S. 121136 General characteristics TypeInland passenger/freight Tonnage63 gross tons, 46 net tons Length72.4 ft (22.07 m) Beam13.6 ft (4.15 m) Depth4.2 ft (1.28 m) depth of hold Deckstwo Installed powerSteam engine Propulsionpropeller CapacityAbout 125 passengers Favorite was a small steamboat that was operated on the …
سفر ناحوممعلومات عامةجزء من أسفار الأنبياء الصغار الاسم المختصر Nah (بالألمانية) العنوان נַחוּם (بالhbo) النوع الفني prophetic books (en) المُؤَلِّف ناحوم entry in abbreviations table Nahum[1] لديه جزء أو أجزاء la ficelleNahum 1 (en) Nahum 2 (en) سفر ميخا تعديل - تعديل مصدري - تعديل ويكي بيانات سفر ناحوم هو السفر ال
Francisco Palomares García Francisco Palomares García (Requena, Comunidad Valenciana, 1838 – Sevilla, 1915) fue un ministro protestante y doctor en medicina. Fue uno de los grandes pilares del protestantismo en España y un referente en la Europa protestante. Uno de los fundadores de la Iglesia española reformada episcopal. Fundador de la Iglesia de San Basilio de Sevilla. Bibliografía Javierre, J.M. (Dir.) y Ros, Carlos (Coor.). Gran Enciclopedia de Andalucía. Sevilla, 1979. Promociones …
نادي الرياضي عمان لكرة السلة معلومات النادي الدوري الدوري الأردني الممتاز لكرة السلة البلد الأردن الموقع مدينة البطولات البطولات 7 أطقم الفريق الطقم الأساسي الطقم الاحتياطي تعديل مصدري - تعديل نادي الرياضي لكرة السلة هو نادٍ محترف لكرة السلة أردني يت
Artikel ini tidak memiliki referensi atau sumber tepercaya sehingga isinya tidak bisa dipastikan. Tolong bantu perbaiki artikel ini dengan menambahkan referensi yang layak. Tulisan tanpa sumber dapat dipertanyakan dan dihapus sewaktu-waktu.Cari sumber: Hipertrofi – berita · surat kabar · buku · cendekiawan · JSTOR Hipertropi adalah hasil peningkatan ukuran sel, sementara hiperplasia adalah bentuk penambahan jumlah sel. Hipertrofi (dari bahasa Yunani ὑπ…
أوكرانيا السوفيتية جمهورية أوكرانيا الاشتراكية السوفيتية Українська Радянська Соціалістична РеспублікаУкраинская Советская Социалистическая Республика ↓ 1919–1991 ↓ جمهورية أوكرانيا الاشتراكية السوفيتيةعلم جمهورية أوكرانيا الاشتراكية السوفيتيةالشعار الشعار الوطني…
Chi1 Orionis A Data pengamatan Epos J2000 Ekuinoks J2000 Rasi bintang Orion Asensio rekta 05h 54m 23.0s Deklinasi +20° 16′ 34″ Magnitudo tampak (V) 4.39 Ciri-ciri Kelas spektrum G0 V Indeks warna U−B 0.07 Indeks warna B−V 0.59 Jenis variabel None AstrometriKecepatan radial (Rv)-13.4 km/sGerak diri (μ) RA: -163.17 mdb/thn Dek.: -98.92 mdb/thn Paralaks (π)113,58±0,69 mdbJarak28,7 ± 0,2 tc (8,80 …
العلاقات الكينية اللبنانية كينيا لبنان كينيا لبنان تعديل مصدري - تعديل العلاقات الكينية اللبنانية هي العلاقات الثنائية التي تجمع بين كينيا ولبنان.[1][2][3][4][5] مقارنة بين البلدين هذه مقارنة عامة ومرجعية للدولتين: وجه المقارنة كينيا لبنان …
This article is about the film. For the 1994 TV sitcom, see Shrimaan Shrimati (TV series). 1982 Indian filmShriman ShrimatiDirected byVijay ReddyWritten byRaj Baldev RajProduced byB. Nagi ReddyStarringSanjeev KumarRaakheeMusic byRajesh RoshanRelease date5 March 1982CountryIndiaLanguageHindi Shriman Shrimati is a 1982 Indian Hindi film produced by B. Nagi Reddy and directed by Vijay Reddy. The film stars Sanjeev Kumar, Raakhee, A. K. Hangal, Amol Palekar, Deepti Naval, Rakesh Roshan, Sarika, Lali…
This article relies excessively on references to primary sources. Please improve this article by adding secondary or tertiary sources. Find sources: Midwestern State Mustangs – news · newspapers · books · scholar · JSTOR (May 2014) (Learn how and when to remove this template message) Midwestern State MustangsUniversityMidwestern State UniversityConferenceLSC (primary)NCAADivision IIAthletic directorKyle WilliamsLocationWichita Falls, TexasVarsity teams13 …
Pusat Berkuda Internasional Sydney (bahasa Inggris: Sydney International Equestrian Centre) (SIEC disingkat) adalah fasilitas yang digunakan untuk menyelenggarakan acara berkuda selama Olimpiade Musim Panas 2000 dan Paralimpiade Musim Panas 2000. Pusat ini terletak 45 kilometer dari Sydney's kawasan bisnis dan harbour di Saxony Road, Horsley Park. Konstruksi dimulai pada tahun 1997, selesai pada tahun 1999 dan berhasil menjadi tuan rumah acara berkuda Olimpiade dan Paralimpiade pada tahun 20…
Spanish music genre and dance Aragonese jota dancers The jota (pronounced [ˈxota][1]) is a genre of music and the associated dance known throughout Spain, most likely originating in Aragon. It varies by region, having a characteristic form in Aragon (where it is the most important[1]), Catalonia, León, Castile, Navarre, Cantabria, Asturias, Galicia, La Rioja, Murcia and Eastern Andalusia. Being a visual representation, the jota is danced and sung accompanied by castanet…
В Википедии есть статьи о других людях с такой фамилией, см. Бернштейн. Анри Бернштейнфр. Henri Bernstein Имя при рождении фр. Henri Léon Gustave Charles Bernstein Дата рождения 20 июня 1876(1876-06-20)[1][2][…] Место рождения VIII округ Парижа, Париж, Франция[5] Дата смерти 27 ноября 1953(1953-11-27)[…
Belarusian judoka Andrei KazusenokKazusenok (right) at the 2015 European Games.Personal informationNative nameAndrei Fyodorovich KazusenokBorn15 January 1984 (1984-01-15) (age 39)Babruysk, BelarusOccupationJudokaSportCountryBelarusSportJudo, SamboWeight class–90 kgAchievements and titlesWorld Champ. (2005)European Champ. (2009) Medal record Men's judo Representing Belarus World Championships 2005 Cairo –90 kg European Championships 2009 Tbilisi –90 kg 2008 Lisbon –90…
This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed.Find sources: List of Yu-Gi-Oh! 5D's characters – news · newspapers · books · scholar · JSTOR (November 2008) (Learn how and when to remove this template message) The following is a list of characters from the Yu-Gi-Oh! 5D's anime series. Names refer to the 4K Media English ver…
Эмиль Молленхауэр Основная информация Дата рождения 4 августа 1855(1855-08-04) Место рождения Бруклин, Нью-Йорк, Нью-Йорк, США Дата смерти 10 декабря 1927(1927-12-10) (72 года) Страна США Профессии дирижёр, скрипач Инструменты скрипка Автограф Медиафайлы на Викискладе Эмил…
Lokasi Pengunjung: 18.118.126.57